Passover 2016: When is the Jewish holiday of Pesach and what is it all about?

Men say prayers during a ritual the night before the beginning of PassoverGetty

Jewish communities will celebrate the festival of Passover this week, one of the most important celebrations in Judaism which commemorates the liberation of the Israelites from slavery.

Passover begins on the 15th day of the Hebrew month of Nisan, which typically falls in March or April of the Gregorian calendar. This year, Passover starts today (22 April) and ends on Saturday 30 April.

According to the Book of Exodus in the Torah, Moses called for the pharaoh to free the Israelites, warning that Egypt would be struck by plagues if he refused. According to the script, the last plague would be the death of every Egyptian first-born male.

The pharaoh remained unmoved, despite plagues of frogs, flies, the death of livestock and total darkness. To avoid the killing of all Egyptian first-born males, Moses urged Jews to mark their doors with lamb's blood to spare the men – after which the pharaoh relented, allowing the Israelites to leave Egypt. The word "pesach" comes from the Hebrew root Pei-Samekh-Cheit, meaning to "pass over" or to spare.

An Indian man prepares unleavened bread for the Jewish Passover festivalGetty

How is Passover celebrated?

On the first two days and the last two days, Jewish people light holiday candles at night and prepare special meals. Most try to refrain from working or driving during this time. During the middle four days, Chol HaMoed, most forms of work are permitted.

An unleavened bread called matzah is traditionally eaten in commemoration of the Jews fleeing Egypt. It is believed they escaped in such a rush that their bread did not have time to rise.

During the festival, Jewish communities try not to consume any chametz – food or drink that contains leavened grain. This includes bread, sweets, pasta and most alcoholic beverages.

On the first night of Passover, it is traditional for Jewish families to gather together for a dinner called a Seder, derived from the word for "order" in Hebrew. During the meal, the story of the exodus from Egypt is retold using a special text called the Haggadah, while four cups of wine are drunk at various stages of the narrative. An extra cup is left for the prophet Elijah, who is believed to reappear and announce the coming of the Messiah.